Naturally occurring and industry-related arsenic contaminates groundwater at high levels in many countries, including Chile, China, Hungary and Mexico, researchers said.

The odourless, tasteless element can cause skin discolouration, stomach pain, partial paralysis and a range of other serious health problems.

While the technology for removing arsenic from water exists and is in widespread use in industrialized areas, it is expensive and impractical for rural and developing regions.

Scientists have been exploring the use of natural waste materials such as banana peels and rice hulls for removing arsenic from water, but these so far have shown limited efficiency.

Recognizing that the porous structure of cigarette ash could be better suited to this purpose, Jiaxing Li at the Chinese Academy of Sciences and colleagues decided to test it.

In a simple, inexpensive, one-step method, the researchers prepared cigarette ash with a coating of aluminum oxide.

When they tested the material with contaminated ground water, they found it removed more than 96 percent of the arsenic, reducing its levels to below the standard set by the World Health Organization.

Because cigarette ash is discarded in countries around the world and can be easily collected in places where public smoking is allowed, it could be part of a low-cost solution for a serious public health issue, researchers said.

The study was published in American Chemical Society's journal Industrial & Engineering Chemistry Research.